混凝土在循环荷载下变形特性及加载曲线包络线的研究

Study on Deformation Properties and Envelop Curve of Loading under Cyclic Load for Concrete

为研究混凝土在循环荷载下的变形特性,进行了2种不同应变速率下(10^(-5)/s,10^(-4)/s)混凝土轴向循环加卸载试验,对混凝土残余塑性应变与卸载点应变的关系及其共同点应变与卸载点应变的关系进行深入分析,并采用改进的Weibull统计模型对循环加卸载曲线的包络线进行拟合。研究结果表明:混凝土在循环加卸载作用下应力应变曲线的包络线与单调荷载作用下的应力应变全曲线基本一致;改进后的Weibull统计模型能较好地拟合包络线。

In order to study deformation behaviors of concrete under cyclic loading, we performed axial cyclic load- ing and unloading tests of concrete at two strain rates （ 10-5/s and 10-4/s）.Relationship between the residual plastic strain of concrete and unloading point strain were analyzed, as well as the relationship between common point strain and the unloading point strain. Envelope curves of stress-strain under cyclic loading and unloading were fitted by u- sing improved Weibull statistical model. The results show that, envelope curves of stress-strain under cyclic loading and unloading are basically in correspondence with stress-strain curves under monotonic loading; moreover , enve- lope curves can be well fitted with the improved Weibull statistical model.